can't save a process if use '<' or '>' in a sequence Flow's name

1- create a diagram in web-designer with these component : a)start node b)task c)end node d)q sequence connecting start node to task e)a sequence connecting task to end 2-put '<' as name of first sequence 3-put '>' as name of second sequence 4- save process 5- re-open the diagram , there is nothing there !!!!!